Tube and method of making the same



Patented July 3, 1934 omrso STATES PATENT No Drawing. Application October 2, 1930, Serial No. 486,057

15 Claims.

This invention relates to the making of tubes or other hollow elongated bodies having walls of plastic composition containing derivatives of cellulose, and relates more particularly to the formation of such tubes from sheets or films containing derivatives of cellulose.

An object of my invention is to form tubes or other hollow elongated bodies in an economical and expeditious manner by winding sheets or tubes of plastic material containing derivatives of cellulose which are softened by means of a softening or swelling agent for the derivative of cellulose. Other objects of my invention will appear from the following detailed description.

It has previously been proposed to form tubes by winding sheets containing cellulose nitrate on a mandrel while immersed in a bath of a solvent for the cellulose nitrate. However the use of a solvent for this purpose is attended with many J disadvantages. The solvent dissolves part of the sheet material which enters into solution in thesolvent bath. Because of this, not only is part of the valuable sheet material lost, but the bath becomes progressively charged with the derivative of cellulose and therefore its strength is altered. For this reason it is necessary to re place the bath with fresh solvent and distill the spent bath to recover the solvent and the derivative of cellulose. Moreover the solvent is tenaciously held in the roll or the tube that is formed and a long seasoning is necessary in order to remove such solvent.

I have found that if instead of employing a liquid that is a solvent for the derivative of cellulose to soften the same, there is employed a material that has only a swelling or softening action on the derivative of cellulose, the above disadvantages are avoided. The action of the swelling or softening agent is less drastic than that of the solvent and therefore the derivative of cellulose is not dissolved from the sheet being wound. The swelling or softening agent therefore does not change in strength and need not be regenerated. Moreover whatever softening agent is incorporated in the finished tube may be easily removed, since it is not held so tenaciously as is a solvent.

In accordance with my invention I form. tubes by winding sheets or films comprising a plastic composition containing a derivative of cellulose in the presence of a swelling agent for the derivative of cellulose while applying pressure to cause the layers of sheets or films to adhere and amalgamate together.

Any elongated hollow body having a hole or bore therethrough may be made by this invention. These may be not only long tubes and short tubes, but barrels for pencils, fountain pens and other articles of manufacture. For brevity all such materials are referred to hereinafter as 5g tubes.

The sheets or films to be wound comprise a plastic composition containing any suitable derivative of cellulose such as cellulose nitrateor organic derivatives of cellulose such as organic esters of cellulose and cellulose ethers. Examples of such organic esters of cellulose are cellulose acetate, cellulose formate, cellulose propionate and cellulose butyrate, while examples of cellulose ethers are ethyl cellulose, methyl cellulose and benzyl cellulose. Besides the derivative of cellulose, the tubes or films will contain suitable plasticizers such as camphor for cellulose nitrate or other well known plasticizers for derivatives of cellulose such as diethyl phthalate, dibutyl phthalate, diethyl tartrate, dibutyl tartrate, triacetin, monomethyl xylene sulfonamid.

The sheets or films to be wound may be transparent, translucent or opaque and may be colorless or may have any suitable pigment dye or effect material incorporated therein to produce mottled, variegated or other differential effects or pearl-like or naoreous appearance. In building up the tubes, sheets or films of the same constitution may be used throughout. On the other hand sheets of different kinds may be used in building up the tubes, for instance the interior of the tubes may be made of cheaper material while the outer part of the tubes may be made of more expensive material such as sheets having pearl-like effects. In building up the tube, films cast upon the smooth surfaces of wheels, bands or stationary fiat surface may be used. If desired, sheets which have been planed from blocks may be used for this purpose.

In order to cause the layers of the films or tubes to adhere to each other, they are wound in the presence of a swelling or softening agent for the derivative of cellulose present. Any suit- 10o able swelling or softening agent may be employed. An example of such softening agent in the case of cellulose nitrate or cellulose acetate is chloroform. Examples of softening agents in the case of acetone-soluble cellulose acetate are ethyl al- 05 cohol, methyl alcohol, diacetone alcohol, or the monoethyl ether of ethylene glycol or aqueous solutions of acetone, acetic acid, lactic acid, glycolic acid, phenol, the thiocyanates of sodium, potassium, ammonium or calcium etc. In case 1 of solutions of solvents in water or other diluents, the concentration of the solvent should be sulficiently low that the liquid has only a swelling or softening action and not a real solvent action on the derivatives of cellulose present. However the softening action on the material should be sufiiciently great so that the sheets or films adhere to each other.

The softening agent is preferably applied by causing the sheets or films to be wound on a mandrel while immersed in a bath of the softening agent. However other expedients may be employed such as spraying the softening agent onto the films or sheets or causing the sheets or films to pass through a bath of the softening agent while on the way to the mandrel or other winding device.

Preferably the sheets or films are rolled on a mandrel while pressure is applied. This may be done by causing a roll. to press, under the actionof spring tension or by weights, against the periphery ofthe roll or tube of plastic ma terial that is being wound.

If sufficient consolidation or amalgamation of the sheets or films in the roll or tube has not been attained by the mere application of pressure, the tube or roll may be placed in a mold, either While on its mandrel or after the removal of the mandrel and the insertion of a core piece, and heat and pressure applied to cause further and complete consolidation of the material.

The tube that is formed is then free of its mandrel and is ready for immediate use, or iI I required, residual softening. agent may be removed by a comparatively short seasoning process.

It will thus be seen that by my invention tubes of plastic material containing derivatives of cellulose may be made economically and such tubes have properties that are superior to tubes formed either in the presence of a solvent or by extru sion through dies.

It is to be understood that the foregoing description is given merely by way of illustration and that many variations may be made therein,

without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

1. The method of forming tubes comprising winding a sheet or film of a plastic composition .containing a derivative of cellulose into a roll in the presence of a substance that softens but does not dissolve said plastic composition.

2. The method of forming tubes comprising winding a sheet or film of a plastic composition containing cellulose acetate into a roll in the presence of a substance that softens but does not dissolve said plastic composition.

3. The method of forming tubes comprising winding a sheet or film of a plastic composition containing cellulose nitrate into a roll in the presence of a substance that softens but does not dissolve said plastic composition.

4. The method of forming tubes comprising Winding a sheet or film of a plastic composition containing a derivative of cellulose into a roll on a mandrel while immersed in a bath of a substance that softens but does not dissolve said plastic composition.

5. The method of forming tubes comprising winding a sheet or film of a plastic composition containing cellulose acetate into a roll on a mandrel while immersed in a bath of a substance that softens but does not dissolve said plastic composition.

6. The method of forming tubes comprising Winding a sheet or film of a plastic composition containing cellulose nitrate into a roll on a mandrel While immersed in a bath of a substance that softens but does not dissolve said plastic composition.

'7. The method of forming tubes comprising winding a sheet or film of a plastic composition containing a derivative of cellulose into a roll in the presence of a substance that softens but does not dissolve said plastic composition and applying pressure to the periphery of the roll to cause adhesion of the layers of the material.

8. The method of forming tubes comprising winding a sheet or film of a plastic composition containing a derivative of cellulose into a roll on a mandrel while immersed in a bath of a substance that softens but does not dissolve said plastic composition and applying pressure to the periphery of the roll to cause adhesion of the layers of the material.

9. The method of forming tubes comprising winding a sheet or film of a plastic composition containing a derivative of cellulose into a roll in the presence of a substance that softens but does not dissolve said plastic composition and then causing further consolidation of the material by application of heat and pressure.

10. The method of forming tubes comprising winding a sheet or film of a plastic composition containing a derivative of cellulose into a roll on a mandrel while immersed in a bath of a substance that softens but does not dissolve said plastic composition and then causing further consolidation of the material by the application of heat and pressure.

11. The method of forming tubes comprising winding a sheet or film of a plastic composition containing a derivative of cellulose into a roll in the presence of a substance that softens but does not dissolve said plastic composition and then removing said substance from the tube that is formed.

12. The method of forming tubes comprising winding a sheet or film of a plastic composition containing cellulose acetate into a roll in the presence of a substance that softens but does not dissolve said plastic composition and then removing said substance from the tube that is formed.

13. The method of forming tubes comprising winding a sheet or film of a plastic composition containing cellulose acetate into a roll in the presence of ethyl alcohol and then removing said substance from the tube that is formed.

14. The method of forming tubes comprising winding a sheet or film of a plastic composition containing cellulose acetate into a roll in the presence of the monoethyl ether of ethylene glycol.

15. The method of forming tubes comprising winding a sheet or film of a plastic composition containing cellulose acetate into a roll on a mandrel while immersed in a bath containing the monoethyl ether of ethylene glycol and then causing further consolidation of the material by the application of heat and pressure.

CAMILLE DREYFUS. 

